The present invention relates in general to solar distillation of fluids and, more particularly, it relates to a still unit for purifying water that is saline, brackish or otherwise unsafe or unpleasant for consumption.
Within the United States, most of the so-called "hard water" areas lie in the Sun Belt, where solar radiation is plentiful. While zeolite filters and other water softening devices may be installed in pressurized domestic water systems they are expensive, and require either back-washing or, more frequently, filter replacement, also an expensive factor. In remote areas, such conveniences are not available, and means to provide safe, potable water, even if only a gallon or two per day, are needed.
More important, over much of the equatorial tropic and sub-tropic zones of the earth, piped water systems and water purification are unknown, and the water supply is at all times an at least potential health hazard. With particular respect to infants, it is a hazard to life itself.
Units for solar distillation of water or other fluids are far from new. A sloped structure including a plurality of fluid trays arranged in step-wise fashion was patented by Wheeler et al in 1870, No. 102,633, and there are likely older examples. A similar structure is disclosed in the French patent of Pasteur, No. 883,117, issued in 1943. More recently, a foamed plastic structure including sloped steps was disclosed by Hensley et al, U.S. Pat. No. 3,655,517, in 1972.
It is not known if any of these or similar units were marketed in the past and as for the present, a unit was rumored as being manufactured in Western Australia, but the manufacturer could not be located.
Of course, to be economically viable any such unit must be widely distributed or sold in areas of need, and the cost must be small. Yet, a successful solution must incorporate a good amount of sophisticated technology in both materials and manufacturing. Such technology is not available at an economic distance from the ultimate consumers, on a world-wide basis. The present invention overcomes this problem by concentrating the technological aspects at the "front" or raw-materials end, coupled with an extremely simple assembly operation that can be carried out with simple tools and only minimal instruction.